feat: ✨ Implement Prometheus support

app.ts

@@ -4,6 +4,7 @@ import { Hono } from "@hono/hono";
 import { cors } from "@hono/hono/cors";
 import { prettyJSON } from "@hono/hono/pretty-json";
 import { secureHeaders } from "@hono/hono/secure-headers";
+import { prometheus } from "@hono/prometheus";
 import { getLogger } from "@logtape/logtape";
 import { config } from "~/packages/config-manager/index";
 import { agentBans } from "./middlewares/agent-bans";
@@ -22,6 +23,18 @@ export const appFactory = async () => {
         strict: false,
     });
 
+    const { printMetrics, registerMetrics } = prometheus({
+        collectDefaultMetrics: true,
+        metricOptions: {
+            requestsTotal: {
+                customLabels: {
+                    content_type: (c) =>
+                        c.res.headers.get("content-type") ?? "unknown",
+                },
+            },
+        },
+    });
+
     app.use(ipBans);
     app.use(agentBans);
     app.use(bait);
@@ -68,6 +81,8 @@ export const appFactory = async () => {
             credentials: true,
         }),
     );
+    app.use("*", registerMetrics);
+    app.get("/metrics", printMetrics);
     // Disabled as federation now checks for this
     // app.use(urlCheck);
 

package.json

@@ -99,6 +99,7 @@
         "@bradenmacdonald/s3-lite-client": "npm:@jsr/bradenmacdonald__s3-lite-client",
         "@hackmd/markdown-it-task-lists": "^2.1.4",
         "@hono/hono": "npm:@jsr/hono__hono@4.5.6",
+        "@hono/prometheus": "^1.0.1",
         "@hono/zod-validator": "^0.2.2",
         "@inquirer/confirm": "^3.1.22",
         "@inquirer/input": "^2.2.9",
@@ -136,6 +137,7 @@
         "oauth4webapi": "^2.12.0",
         "ora": "^8.0.1",
         "pg": "^8.12.0",
+        "prom-client": "^15.1.3",
         "qs": "^6.13.0",
         "sharp": "^0.33.5",
         "sonic-channel": "^1.3.1",